229 lines
9.0 KiB
C#
229 lines
9.0 KiB
C#
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#region PDFsharp - A .NET library for processing PDF
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//
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// Authors:
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// Stefan Lange
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//
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// Copyright (c) 2005-2017 empira Software GmbH, Cologne Area (Germany)
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//
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// http://www.pdfsharp.com
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// http://sourceforge.net/projects/pdfsharp
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the "Software"),
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// to deal in the Software without restriction, including without limitation
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// the rights to use, copy, modify, merge, publish, distribute, sublicense,
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// and/or sell copies of the Software, and to permit persons to whom the
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// Software is furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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// DEALINGS IN THE SOFTWARE.
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#endregion
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using System;
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using System.Diagnostics;
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using System.Collections.Generic;
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using System.Globalization;
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using PdfSharp.Drawing;
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namespace PdfSharp.Pdf.Advanced
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{
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/// <summary>
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/// Contains all external PDF files from which PdfFormXObjects are imported into the current document.
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/// </summary>
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internal sealed class PdfFormXObjectTable : PdfResourceTable
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{
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// The name PdfFormXObjectTable is technically not correct, because in contrast to PdfFontTable
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// or PdfImageTable this class holds no PdfFormXObject objects. Actually it holds instances of
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// the class ImportedObjectTable, one for each external document. The PdfFormXObject instances
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// are not cached, because they hold a transformation matrix that make them unique. If the user
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// wants to use a particual page of a PdfFormXObject more than once, he must reuse the object
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// before he changes the PageNumber or the transformation matrix. In other words this class
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// caches the indirect objects of an external form, not the form itself.
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/// <summary>
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/// Initializes a new instance of this class, which is a singleton for each document.
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/// </summary>
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public PdfFormXObjectTable(PdfDocument document)
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: base(document)
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{ }
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/// <summary>
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/// Gets a PdfFormXObject from an XPdfForm. Because the returned objects must be unique, always
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/// a new instance of PdfFormXObject is created if none exists for the specified form.
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/// </summary>
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public PdfFormXObject GetForm(XForm form)
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{
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// If the form already has a PdfFormXObject, return it.
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if (form._pdfForm != null)
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{
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Debug.Assert(form.IsTemplate, "An XPdfForm must not have a PdfFormXObject.");
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if (ReferenceEquals(form._pdfForm.Owner, Owner))
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return form._pdfForm;
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//throw new InvalidOperationException("Because of a current limitation of PDFsharp an XPdfForm object can be used only within one single PdfDocument.");
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// Dispose PdfFromXObject when document has changed
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form._pdfForm = null;
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}
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XPdfForm pdfForm = form as XPdfForm;
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if (pdfForm != null)
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{
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// Is the external PDF file from which is imported already known for the current document?
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Selector selector = new Selector(form);
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PdfImportedObjectTable importedObjectTable;
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if (!_forms.TryGetValue(selector, out importedObjectTable))
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{
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// No: Get the external document from the form and create ImportedObjectTable.
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PdfDocument doc = pdfForm.ExternalDocument;
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importedObjectTable = new PdfImportedObjectTable(Owner, doc);
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_forms[selector] = importedObjectTable;
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}
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PdfFormXObject xObject = importedObjectTable.GetXObject(pdfForm.PageNumber);
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if (xObject == null)
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{
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xObject = new PdfFormXObject(Owner, importedObjectTable, pdfForm);
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importedObjectTable.SetXObject(pdfForm.PageNumber, xObject);
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}
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return xObject;
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}
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Debug.Assert(form.GetType() == typeof(XForm));
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form._pdfForm = new PdfFormXObject(Owner, form);
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return form._pdfForm;
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}
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/// <summary>
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/// Gets the imported object table.
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/// </summary>
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public PdfImportedObjectTable GetImportedObjectTable(PdfPage page)
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{
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// Is the external PDF file from which is imported already known for the current document?
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Selector selector = new Selector(page);
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PdfImportedObjectTable importedObjectTable;
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if (!_forms.TryGetValue(selector, out importedObjectTable))
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{
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importedObjectTable = new PdfImportedObjectTable(Owner, page.Owner);
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_forms[selector] = importedObjectTable;
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}
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return importedObjectTable;
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}
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/// <summary>
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/// Gets the imported object table.
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/// </summary>
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public PdfImportedObjectTable GetImportedObjectTable(PdfDocument document)
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{
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if (document == null)
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throw new ArgumentNullException("document");
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// Is the external PDF file from which is imported already known for the current document?
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Selector selector = new Selector(document);
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PdfImportedObjectTable importedObjectTable;
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if (!_forms.TryGetValue(selector, out importedObjectTable))
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{
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// Create new table for document.
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importedObjectTable = new PdfImportedObjectTable(Owner, document);
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_forms[selector] = importedObjectTable;
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}
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return importedObjectTable;
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}
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public void DetachDocument(PdfDocument.DocumentHandle handle)
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{
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if (handle.IsAlive)
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{
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foreach (Selector selector in _forms.Keys)
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{
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PdfImportedObjectTable table = _forms[selector];
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if (table.ExternalDocument != null && table.ExternalDocument.Handle == handle)
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{
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_forms.Remove(selector);
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break;
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}
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}
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}
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// Clean table
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bool itemRemoved = true;
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while (itemRemoved)
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{
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itemRemoved = false;
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foreach (Selector selector in _forms.Keys)
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{
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PdfImportedObjectTable table = _forms[selector];
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if (table.ExternalDocument == null)
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{
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_forms.Remove(selector);
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itemRemoved = true;
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break;
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}
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}
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}
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}
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/// <summary>
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/// Map from Selector to PdfImportedObjectTable.
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/// </summary>
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readonly Dictionary<Selector, PdfImportedObjectTable> _forms = new Dictionary<Selector, PdfImportedObjectTable>();
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/// <summary>
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/// A collection of information that uniquely identifies a particular ImportedObjectTable.
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/// </summary>
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public class Selector
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{
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/// <summary>
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/// Initializes a new instance of FormSelector from an XPdfForm.
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/// </summary>
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public Selector(XForm form)
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{
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// HACK: just use full path to identify
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_path = form._path.ToLowerInvariant();
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}
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/// <summary>
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/// Initializes a new instance of FormSelector from a PdfPage.
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/// </summary>
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public Selector(PdfPage page)
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{
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PdfDocument owner = page.Owner;
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_path = "*" + owner.Guid.ToString("B");
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_path = _path.ToLowerInvariant();
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}
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public Selector(PdfDocument document)
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{
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_path = "*" + document.Guid.ToString("B");
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_path = _path.ToLowerInvariant();
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}
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public string Path
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{
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get { return _path; }
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set { _path = value; }
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}
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string _path;
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public override bool Equals(object obj)
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{
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Selector selector = obj as Selector;
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if (selector == null)
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return false;
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return _path == selector._path;
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}
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public override int GetHashCode()
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{
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return _path.GetHashCode();
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}
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}
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}
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}
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